This invention is in the field of ultrasound based measurement techniques, and relates to a measurement method and device for determining a specific location in a patient""s bone, particularly useful for facilitating dental treatment by determining an appropriate drilling depth.
It is a typical dental procedure to use endosseous osseointegrated root for implants for tooth replacement in the posterior Audible. This process requires the drilling of an implant-receiving cavity. Before commencing the drilling, an investigation is made to determine the length of the longest physiologically possible implant which can be safely implanted whilst leaving sufficient alveolar bone tissue (typically of about 2 mm) above the superior border of the mandibular canal in the posterior mandible, through which the plexus of nerves extends. A term xe2x80x9cnerve canalxe2x80x9d will be used herein to refer to a specific location of which contact, such as by drilling, is to be avoided. The mandibular canal of the posterior mandible is one example. In the case when the nerve canal includes nerves, contact often results in the undesired perforation thereof.
Known dental techniques for determining the length of the longest physiologically possible implant utilize panoramic X-ray radiography or CT scans. To avoid the possible puncture of the mandibular canal, implants shorter than those that are physiologically safe are typically performed. Such implants, however, suffer from reduced osseointegration with the surrounding bone tissue and are therefore less successful.
It is also important that the condition of the posterior mandible and the posterior maxilla be assessed prior to drilling an implant receiving cavity, in order to determine whether the bone is suitable for receiving an implant and to avoid unnecessary surgical performance. Such an assessment may be carried out by examining the porosity of the bone tissue.
WO 01/00102, assigned to the assignee of the present application, discloses an ultrasound-based technique for achieving the above purposes. According to this technique, a single ultrasonic probe is applied to the patient""s jaw from the interior of the patient""s mouth.
There is accordingly a need in the art to facilitate the location of a nerve canal in a patient""s bone to thereby facilitate treatment, such as dental procedures, aimed at drilling a cavity in bone, by providing a novel measurement system and method.
The present invention utilizes an ultrasound-based measurement technique, and provides for locating a nerve canal in the bone. Considering a dental treatment, the present invention allows for determining the length of the longest physiologically possible implant defining a drilling depth. This can be implemented either by utilizing ultrasound measurements and a preliminary drilling procedure, prior to starting the implant drilling, or by taking ultrasound measurements that enable three-dimensional imaging of the patient""s bone. Additionally, the invention provides for determining the velocity of sound propagation through the bone tissue that is indicative of the porous condition thereof.
Generally, the present invention can assist in any treatment of the kind in which preventing a specific location in the bone from being contacted during the treatment is desired.
The main idea of the present invention consists of using two ultrasonic probes, wherein at least one of the probes is operable as a transceiver, and the other may be a receiver or a transceiver. The probes are applied at opposite sides of the bone which is to be treated, and operate together to measure the distance between the receiver and a nerve canal in the bone at two different states of the bone, respectively, prior to and after the bone has undergone a certain preliminary drilling. By this, an optimal drilling preventing the nerve canal from being contacted can be determined.
Thus according to one broad aspect of the present invention, there is provided a measurement device for use in treatment of a patient""s bone, containing a specific location, which is of the kind reflecting ultrasonic radiation and which is to be prevented from being contacted during the treatment, the measurement device comprising:
(i) two ultrasound probes that are to be located at opposite sides of the bone, at least one of the probes being a transceiver, the two probes being operable to communicate with each other to generate measured data indicative of a relative position of said location in the bone with respect to the probes; and
(ii) an electronic assembly connectable to the probes, so as to selectively operate each of them, and to be responsive to the measured data to thereby enable the determination of said relative position.
According to one embodiment of the invention, the transceiver and receiver are used to measure the distances between the receiver and the specific location in the bone at two different states of the bone, respectively, prior to and after the bone has undergone a certain preliminary drilling. By this, an optimal drilling depth preventing the specific location from being contacted can be determined. According to another embodiment of the invention, the probes are two arrays, respectively, of ultrasound transceivers, enabling three-dimensional imaging of the bone including the nerve canal.
Thus according to another broad aspect of the present invention, there is provided a measurement device for use in treatment of a patient""s bone including a drilling of the bone, wherein the bone contains a specific location of the kind reflecting ultrasonic radiation which is to be prevented from being contacted during the drilling, the measurement device comprising:
(a) a first ultrasonic probe for applying to said bone from one side thereof, the first probe being a transceiver operable to transmit ultrasound radiation. through the bone, to receive the ultrasound radiation returned from said location within the bone, and to generate first measured data representative of the received radiation, said first data being indicative of a location of the transceiver with respect to said location in the bone and indicative of a distance between the transceiver and said location;
(b) a second ultrasonic probe for applying to sad bone at the opposite side thereof, the second probe being a receiver operable to receive the ultrasound radiation transmitted by said transceiver through the bone, and to generate second measured data representative of the radiation received by the receiver; said second data being indicative of a relative location of the receiver with respect to the transceiver and indicative of a distance between the receiver and the transceiver; and
(c) an electronic assembly associated with the transceiver and to the receiver, so as to selectively operate each of them, and to be responsive to the measured data to thereby enable desired positioning of the transceiver and the receiver, and enable the determination of a relative position of said location in the bone with respect to the receiver to be used for determining and optimal drilling depth preventing said location from being contacted.
More specifically, the present invention is used in dental treatments including drilling of a patient""s alveolar bone. To this end, two ultrasonic probes are applied to the opposite sides of the patient""s jaw, respectively. One of the probes may be applied from the interior and the other from the exterior of the patient""s mouth. The external probe is operable as a transceiver, and the internal probe is operable as a receiver. The independent operation of the transceiver enables its desired positioning with respect to the nerve canal within the jaw. When the transceiver is fixed in the desired location, the receiver is put into operation at the opposite side of the jaw to detect signals transmitted by the transceiver, in order to provide a desired positioning of the receiver with respect to the transceiver. Then, a measurement session is performed by both probes consisting of at least two time of flight measurements, wherein one measurement is taken prior to a preliminary drilling of a preset depth, and the other is taken thereafter.
Both probes may be applied to opposite sides of the bone from the interior of the patient""s mouth. In this case, the probes are arrays of transceivers, and are sequentially operated to create a three-dimensional image of the bone including the nerve canal, which image is then used for guiding the bone treatment.
Thus, according to yet another broad aspect of the present invention, there is provided a measurement device, which is to be used in dental treatment including a drilling of a patient""s alveolar bone, the measurement device comprising:
(a) a fist ultrasonic probe for applying to the patient""s jaw from the exterior of the patient""s mouth, the first probe being a transceiver operable to transmit ultrasound radiation through the alveolar bone, to receive the ultrasound radiation returned from a nerve canal within the bone, and generate first measured data representative of the received radiation, said first data being indicative of a relative location of the transceiver with respect to the nerve canal thereby enabling a desired positioning of the transceiver, and indicative of a distance between the transceiver and said nerve canal;
(b) a second ultrasonic probe for applying to the patient""s jaw from the interior of the patient""s mouth, the second probe being a receiver operable to detect the ultrasound radiation transmitted by said transceiver through the bone, and to generate second measured data representative of the radiation received by the receiver, said second data being indicative of a relative location of the receiver with respect to the transceiver, thereby enabling a desired positioning of the receiver, and indicative of a distance between the receiver and the transceiver; and
(c) all electronic assembly associated with the transceiver and the receiver to analyze the measured data to enable said desired positioning of the transceiver and the receiver, and enable the determination of a distance between the receiver and the nerve canal to be used for determining and optimal drilling depth.
According to yet another aspect of the present invention, there is provided a dental treatment system comprising an ultrasonic measurement device associated with a drilling tool for drilling a cavity in a patient""s alveolar bone, wherein:
the measurement device comprises:
two ultrasound probes that are to be located at opposite sides of the bones at least one of the probes being a transceiver, the two probes being operable to communicate with each other to generate measured data indicative of a relative position of said location in the bone with respect to the probes; and
an electronic assembly associated with the probes, so as to selectively operate each of them, and to be responsive to the measured data to enable the determination of said relative position, and thereby the determination of an optimal drilling depth;
the system is operable to activate the measurement device to take measurements and utilize the measured data to guide the drilling tool.